The application relates to vehicle occupant restraint systems and to a method for distributing gas between two airbag chambers of an airbag, and to a method for increasing the internal pressure in a partial region of an airbag.
Multipart airbags for vehicle occupant restraint systems, which have at least one first and one second airbag chamber, are generally known. Multichamber airbags of this type are used, for example, in side airbag systems, the airbag forming, for example, a thorax chamber and a head chamber. A multichamber airbag of this type is described in U.S. 5-A-5,718,450.
EP 1 375 262 A1 and EP 0 835 193 B1 describe airbag systems, in which an inner bag or a tube is situated in the interior of a main chamber of an airbag and, when the airbag is deployed, is rolled back outwards. In this case, the parts which are rolled back outwards have a discharge opening. The effect of the airbag systems described is to provide a discharging of gas from a discharge opening in a manner offset in terms of time by the regions which are arranged on the inside first of all having to be rolled back outwards.
EP 1 022 198 A1 discloses an airbag system, in which a discharge opening of an airbag is closed on its outer side by an elastic membrane. The elastic membrane expands without being separated from the airbag in the event of the airbag interacting with a vehicle occupant and there being an associated increase in pressure in the airbag. In this case, a low equalizing volume is provided.
DE 100 18 170 A1 describes an airbag arrangement for motor vehicles with an inflatable airbag, the expansion of which is restricted by a restricting casing in the event of an occupant being out of position. In the normal protective case, the restriction casing tears due to a higher internal pressure in this case in the airbag.